The "A Face To Call Home" singer paid tribute to his 28-year-old on/off girlfriend on stage at the opening night of his Born & Raised tour in Milwaukee, Wisconsin, on Saturday night (July 6, 2013).

The 35-year-old singer-songwriter told the audience that the "Wide Awake" singer, whom he recently rekindled his relationship with, is "more incredible than I ever thought" as he opened up about his throat surgery last summer, and explained how it ultimately brought him and Katy, who was at the concert, closer.

He said: "I was just getting to know a girl and started really reconsidering just how difficult everything was going to be, right as he (the doctor) was putting the needle through my neck, because I was just getting to know this girl, and I wasn't going to be able to talk to her.

"And she was more incredible than I ever thought because I would whisper in her ear and she would order for me with the waiter, and I would whisper in her ear and she would tell people, 'It was nice to meet you, he says.' We did a lot of whispering."

He added the couple spent a lot of time chatting online via video when they were apart and he is grateful to Katy for making so much effort when he could barely speak.

He said: "She was so patient as to even continue to get to know me and love me, while we would be on speaker phone."

John then dedicated his new song to the "Firework" hitmaker, saying: "This is a long time coming for us and I want to dedicate this next song to Katy, my Katy."

The couple got back together last month shortly after Katy admitted in an interview that she was still "madly in love" with him.